"A new analysis of licensing data shows that not only is use of the GPL and other copyleft licenses continuing to decline, but the rate of disuse is actually accelerating." This shouldn't be surprising. The GPL is complex, and I honestly don't blame both individuals and companies opting for simpler, more straightforward licenses like BSD or MIT-like licenses.

"[q][q]They'll use OSS as a "base" and stick a proprietary icing on top. The problem here is that since the GPL is "viral", they don't want it to "infect" the proprietary code, thus forcing them to release it (I believe this has happened with the Linksys WRT router).

The GPL is not "viral", it applies ONLY to a package of code released by the author of that code under the GPL.
"

That's MPL. Anything you link with GPL'd software becomes contaminated and is also GPLd. That's one of the reasons why MacOSX doesnt carry GNU readline. [/q]

Except with GPL, you can remove the link and you're no longer infringing. A proper virus doesn't get removed that cleanly. [/q]

The actual truth here is somewhat different, and it is to be found in the text of copyright law.

http://en.wikipedia.org/wiki/Derived_workIn United States copyright law, a derivative work is an expressive creation that includes major, copyright-protected elements of an original, previously created first work (the underlying work).

So, if you write code, it is YOUR code, and you can do with it what you wish, license it however you may.

If however you make a product using someone else's code, you need their permission. If the original author released that code under the GPL, therein is the required permission granted to you, with some conditions attached. You need to re-distribute the source code along with your product. Since it wasn't your code anyway, this shouldn't be a problem in any way.

If you write some code of your own, but to make a whole product you include someone else's code, then you do not actually own the whole product. You have created what is known under copyright law as a "derived work". This happens only when you have included someone else's copyrighted prior work as a major element of your product.

The ownership of the derived work is split between the authors, in proportion to their contributions. If you include only a tiny amount of other people's code, then that is not a "major element" under copyright law, and you can get away with doing that.

But if you do include as a major element of someone else's work in your proprietary product, then you need their permission in order to sell your product, as it isn't entirely yours, it is a derived work of more than one party. The GPL license does NOT cover this, so you ave no permission to go ahead and sell your derived work.

You must get permission, it is a requirement under copyright law. You must get that permission from the copyright holders (in many cases, this is the original authors). It must be a separate arrangement other than the GPL. In other words, you can only do this OUTSIDE of the GPL.

A lot of software is actually made available under multiple licenses.

http://en.wikipedia.org/wiki/Dual_license"Multi-licensing is the practice of distributing software under two or more different sets of terms and conditions. This may mean multiple different licenses or sets of licenses. Prefixes may be used to indicate the number of licenses used, e.g. dual-licensed for software licensed under two different licenses.

When software is multi-licensed, recipients can choose which terms under which they want to use or distribute the software. The distributor may or may not apply a fee to either option."

MySQL is an example. Other examples include Oracle's NetBeans IDE, Asterisk, Oracle Corporation's Berkeley DB, Modelio, ZeroC's Ice, Magnolia CMS and Qt Software's Qt development toolkit. If you want to make a proprietary product which uses MySQL within it, go ahead, but you will need to buy a commercial license for it.

Derived works are OUTSIDE of the GPL. The GPL doesn't permit them. If you want to use code in a commercial product, you need to get a commercial license from the copyright holder.

We have now gone outside of the GPL. We aren't talking about the GPL any more.